1. FIELD OF THE INVENTION
The invention relates generally to the field of surgical instrumentation suitable for endoscopic surgical procedures. More particularly, the invention relates to tissue retracting or manipulating instruments suitable for endoscopic procedures.
2. DESCRIPTION OF THE PRIOR ART
Endoscopic surgical procedures have been used for many years and the popularity of such procedures has recently increased. These procedures employ endoscopes, laparoscopes, cystoscopes and the like, each of which is characterized by an elongated barrel or tube of relatively small diameter which may have a plurality of channels extending between its proximal and distal ends, the latter being inserted into a body cavity. Alternatively, a plurality of single channel tubes may be used. Various elements are inserted into and for illumination of the cavity, another providing visual access into the cavity via fiber optics or the like, while still others provide for insertion and control of specialized surgical tools performing specific functions.
It is particularly important during endoscopic procedures to provide a means for manipulating tissue so that the work area may be properly viewed. The tissue manipulation is generally performed by a tissue retractor and numerous prior art forms of tissue retractors are known.
U.S. Pat. No. 4,393,872 (Reznik et al.) shows one form of tissue retractor utilizing a plurality of resilient fingers which are able to be compressed within the endoscopic tube and, by virtue of their resiliency, spread apart when they are pushed from the tube at the work site. Withdrawing the fingers into the tube causes them to be compressed again in order to enable their withdrawal. These types of retractors are sometimes disadvantageous in that, occasionally, tissue may be caught between the fingers as they are withdrawn.
Another prior art retractor, shown in U.S. Pat. No. 4,190,042, (Sinnreich) comprises a preformed resinous material which is compressible enough to be forced through the endoscopic tube and, upon being pushed from the distal end of the tube, has sufficient memory to produce a relatively rectilinear, scoop-shaped structure. While overcoming some of the disadvantages of other prior art tissue retractors, this device is costly to manufacture and has a greater degree of flexibility than is suitable for certain tissue manipulation.
Some prior art tissue retractors have a push rod extending through the tube which deflects a member at the distal tip of the tube so that the deflected member then extends obliquely relative to the axis of the endoscopic tube. For example, U.S. Pat. No. 4,517,965 (Ellison) shows such a deflectable member as being a retractable barb made of spring steel which, when not biased outwardly by a push rod, is flush with the endoscopic tube.
U.S. Pat. Nos. 3,316,912 (Whitaker), 4,178,920 (Caywood Jr. et al.), and 4,962,770 (Agee et al.) each show an endoscopic type instrument wherein a push rod is pivotably joined at its distal tip to a member which, when the push rod is moved distally, moves into a transverse position relative to the axis of the tube. In each of these instances, the distal member extends only to one side of the endoscopic tube and is, therefore, somewhat limited in its usefulness as a tissue retractor in certain situations.
Several prior art devices are known which have tissue retracting members extending to either side of an endoscopic tube. For example, U.S. Pat. No. 4,608,965 (Anspach Jr. et al.) discloses a "molly bolt" type of structure wherein an outer sheath is provided with a plurality of axially extending flexible tabs circumferentially arranged at its distal tip, the distal end of the tabs being secured to a slidable inner shaft. Retracting the inner shaft relative to the outer shaft causes the ends of the flexible tabs to come together thereby forcing the center of the tabs radially outwardly. This type of arrangement is relatively costly and complex and, because of the necessity for making the tabs resilient, results in a weak device unsuitable in certain situations.
It is an object of this invention to provide a tissue retracting device suitable for endoscopic applications.
It is yet another object of this invention to provide a tissue retracting device suitable for endoscopic application while also being stronger than known tissue retractors and extending transversely to the longitudinal axis of the endoscopic tube.